The present invention relates to the field of hot melt adhesive formulations based on thermoplastic elastomers, which elastomers by their nature are inherently tacky and non-free flowing.
Adhesive compositions using many of the base elastomers, tackifier resins and reinforcing resins are described in U.S. Pat. No. 4,024,312 for use in adhesive tape applications.
U.S. Pat. No. 4,101,484 teaches a formulation for a sealant which has good flexibility and adhesion, but is not tacky after curing.
Many of the base elastomers used in formulating adhesives are inherently tacky and their recovery from the manufacturing process in the form of usable pellets is extremely difficult. Recovery by devolatilizing extrusion into polymer strands which are then put through a pelletizing machine results in tacky strands which cannot be chopped into pellets without gumming up the machinery and without producing a product which is anything but free-flowing.
One method of overcoming the gumming problem has been to cool the extruded strand of elastomer prior to attempting to chop the strand. Some degree of success has been found with this procedure, but once the pellets warm up to room temperature, they become sticky again and stick to one another and to everything they touch.